﻿<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
  "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
  <style type="text/css">
    #container {
      overflow: hidden;
      width: 100%;
    }
    #left-col {
      float: left;
      width: 50%;
      background-color: orange;
      padding-bottom: 500em;
      margin-bottom: -500em;
    }
    #right-col {
      float: left;
      width: 50%;
      margin-right: -1px; /* Thank you IE */
      border-left: 1px solid black;
      background-color: red;
      padding-bottom: 500em;
      margin-bottom: -500em;
    }
</style>
</head>
<body>
  <div id="container">

    <div id="left-col">
      <p>Test content</p>
      <p>longer</p>
    </div>

    <div id="right-col">
      <p>Test content</p>
    </div>

  </div>
</body>